Apparatus for crust breaking



Filed Sept. 5, 1963 1967 K. ELLINGSAETER'ETAL 3,306,

APPARATUS FOR CRUST BREAKING 3 Sheets-Sheet; 1

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6 MM 41 M1 fimw 1967 K. ELLINGSAETER ETAL 3,

APPARATUS. FOR CRUST BREAKING Filed Sept. 5, 1963 5 Sheets-Sheet 2 ML-M 1967 K. ELLINGSAETER ETAL 3,306,668

APPARATUS FOR CRUST BREAKING Filed Sept. 5, 1963 a Sheets-Sheet s K WT EAL/71615195365 15 $465725! United States Patent 3,306,668 APPARATUS FUR CRUST BREAKING Knut Ellingsaeter, Sunndalsora, Ole Georg Gjgts teen,

Ardalstangen, and (lie Naess Rrtveit, Hashim, Norway, assignors to A/S Ardal og Sunndal Verk, Oslo, Norway Filed Sept. 3, 1963, Ser. No. 306,033 Claims priority, application Norway, Sept. 14, 1962, 145,722 6 Claims. (Cl. 299-70) In the production of aluminium by fusion electrolysis of A1 0 which is dissolved in molten cryolite, a crust forms on the top of the electrolytic bath. This crust must be broken and pushed down into the molten electrolyte where it is molten or dissolved.

This work was previously made by means of hand tools, but is now usually accomplished by means of crust breaking apparatuses. A crust breaking apparatus usually consists of a truck movable along the electrolytic cell or furnace, or a series of such cells or furnaces, on which truck is mounted a movable cantilever carrying at its free end a pneumatic drill or hammer, which is the crust breaking tool proper. Instead of a truck it is known to use a crane.

By operation of the truck or crane and the cantilever the tool can be placed at any point on the top of the crust. By numerous rapid blows of the tool the crust is broken. Each time one is going to make a hole in the crust the apparatus has to be placed in position and then a hole is struck. This operation is repeated until the whole crust is knocked down.

Instead of many relatively light blows a strong pressure may be applied to the crust, so that it is pushed down into the electrolytic bath. As the pressure required for this purpose may be very high, such procedure will be laborious. It is obvious that the strength of the crust will depend on the operational conditions, such as the consistence of the oxide used, the age of the crust and the temperature of the electrolytic bath. Further the shape of the tool which is to be pressed through the crust will have significance.

The present invention relates to a crust breaking apparatus comprising a crust breaking tool carried by a support being movable along the electrolytic cell or cells.

One object of the invention is to provide such an apparatus being more eflicient than crust breaking apparatuses hitherto known.

Another object of the invention is to provide a crust breaking apparatus having a greater working efiiciency than known apparatuses.

A further object of the invention is to provide a crust breaking apparatus which can be moved continually along the cell or cells.

A still further object of the invention is to provide a crust breaking apparatus in which the crust breaking tool is not blown or struck against the crust, but is moved continually along the crust, breaking the same while so moved.

The mode of operation of the apparatus according to the invention differs thus in substantial degree from the mode of operation of crust breaking apparatuses previously known. In known apparatuses the tool must be placed in desired position on the crust, whereafter a hole is struck in the crust by numerous rapid blows of the tool. Then the tool must be lifted and moved to a new position, and a second hole is struck in the crust.

According to the present invention the tool is not lifted from the crust during its movement along a cell, and is only lifted when it shall be moved from one cell to a subsequent cell in a series of electrolytic cells, or from one side of a cell to the opposite side.

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According to a preferred embodiment the tool in an apparatus according to the invention has the shape of a wheel being rotatably mounted about a substantially horizontal axis being substantially perpendicular to the movement direction along the cell, which wheel is adapted to roll on the crust simultaneously breaking the same or pushing the same down, in a manner which will be described below.

The wheel can preferably consist of a hub provided with a multiple of rigid elements in the shape of blunt pikes or crow bars, radially mounted on the hub with even intervals in circumferential direction.

However, it is not necessary that the tool should be rotatably mounted. The tool can consist of a rigid element the under side of which slopes upwardly in the movement direction, for instance after the fashion of a sleigh-runner or the bow of an ice breaker.

According to a preferred embodiment of the crust breaking apparatus according to the invention, at least the tool proper, but preferably also the operation stand, are attached to the lower end of a lift and lowerable supporting element being telescopically connected with a second element the upper end of which is carried by a crane moveable in the longitudinal direction of the cell or series of cells. Hereby is obtained that the tool can be lifted when it during its horizontal movement comes to the end of one cell, and lowered down onto the crust in a subsequent cell. If also the operation stand is attached to the said supporting element, the advantage is obtained that the apparatus can be lifted to such a height that it can be moved over trucks or other 0bstacles on the floor along the cell or cells.

Further features and advantages of the invention will be described in the following in connection with the accompanying drawings, illustrating, without limitation, some embodiments of the crust breaking apparatus according to the invention, and some embodiments of crust breaking tools to be used in such apparatuses.

In the drawing:

FIGS. 1-8 show a crust breaking apparatus according to a first embodiment of the invention, and some embodiments of the tool,

FIG. 1 showing diagrammatically the whole apparatus, comprising a truck, adapted to be moved along a cell or a row of cells, a cantilever carried by the truck and being swingably mounted about an axis extending in the movement direction of the truck, and a tool mounted at the end of the cantilever, the whole apparatus shown in working position and in the movement direction,

FIG. 2 showing the tool in FIG. I, seen from the right,

FIGS. 3 and 4 showing a tool according to a modified embodiment, but adapted to be used in an apparatus according to FIG. 1, FIG. 3 showing the tool seen in the movement direction and FIG. 4 seen from the right in FIG. 3,

FIG. 5 and FIG. 6 being views similar to FIG. 3 and FIG. 4 of a further modification of the tool, and

FIGS. 7 and 8 being similar views of a further modification of the tool.

FIG 9 shows a crust breaking apparatus according to a second embodiment of the invention, provided with a tool as shown in FIGS. 1 and 2, which tool however is carried by a crane instead of by a truck, and FIG. 10 is a sectional view along the line X-X in FIG. 9.

FIG. 11 shows a crust breaking apparatus according to a third embodiment of the invention, provided with a tool as shown in FIG. 1 and FIG. 2, and

FIG. 12 is a sectional view along the line XII-XII in FIG. 11.

The crust breaking apparatus according to the embodiment shown in FIG. 1 and FIG. 2 comprises a truck 1 provided with wheels 2, a cantilever 3, and the crust breaking tool proper 4, made in the shape of a wheel being freely rotatably mounted about the axis 55 at the free end of the cantilever. The cantilever is swingably mounted at 6 about an axis extending in the movement direction of the truck, and is adapted to be swung in a vertical plane, for instance by means of a hydraulic mechanism 7, so that the tool is placed and maintained at a desired level.

The tool 4 according to FIGS. 1 and 2 consists of a disc 8 and a number of rod-shaped, rigid elements 9' extending radially from the circumference of the disc. The elements 9 are adapted to be pressed down through the crust when the truck is moved along the cell.

In FIG. 1 is shown in vertical section fragments of a wall 10, an electrolytic bath 11, a crust 12 and an anode 13 of an electrolytic cell.

The apparatus operates as follows:

When the crust breaking process shall be started, the truck 1 is moved to the place where the breaking is to begin, for instance at one end of a cell in a row of cells, and the tool is brought to a position as shown in FIG. 1. Hereby the tool is pressed against the crust 12 in such a manner that one or more of the elements 9 are forced through the crust. This is accomplished by swinging the cantilever in clockwise direction by means of the mechanism 7. The truck is now moved along the cell and the tool is maintained in a constant level relatively to the top surface of the crust. As a result of the contact between the lowermost elements 9 and the crust, the tool being freely rotatably mounted will be rotated about its axis, whereby subsequent elements 9 will come into contact with the crust and be forced down through the same. By this action the crust will be broken or pushed down. In this connection it should be noted that it is not absolutely necessary that the crust is broken into pieces. If the crust is pushed down, so that its under sides comes into contact with the molten electrolyte the crust will be molten and/ or dissolved in the bath.

The tool according to the embodiment shown in FIGS. 3 and 4 comprises two discs 15 and 16 attached to a common hub 14, and each provided with a number of radially extending elements 17 and 18. These elements are, as shown in the drawing, preferably angularly displaced relatively to each other, whereby the crust breaking effect of the elements is increased.

The function of the tool according to FIGS. 3 and 4 will be substantially the same as described in connection with FIG. 1 and FIG. 2.

FIGS. 5 and 6 show a tool in the shape of a wheel comprising a disc 19 but without elements corresponding to the elements 9. The disc 19 is preferably rotatably mounted, but this is not absolutely necessary. If the disc is not freely rotatable, the function will be about the same as the function of the tool shown in FIGS. 7 and 8. This tool is in the shape of sleigh-runner or the like, having an under side 21 sloping upwards in the movement direction of the truck. The element 20 is rigidly attached to the cantilever, and is during the crust breaking operation maintained in a position in which it is penetrating the crust. By movement of the element 20 in direction of the arrow A, and in a constant level in relation to the surface of the crust, the sloping face 21 will press the crust down or cut a path through the same.

In FIGS. 9-12 two further embodiments of a crust breaking apparatus according to the invention are shown. These embodiments differ from the embodiment shown in FIG. 1 therein that the crust breaking tool according to FIGS. 9-12 is carried by a crane and not by a truck. The crust breaking tool proper can be of the same shape and construction as previously described. For simplicitys sake only a tool as shown in FIGS. 1 and 2 is shown in the embodiments being described in the following.

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Further, it should be noted that different kinds of cranes can be used, for instance traverse cranes.

In FIG. 9 the crust breaking tool is shown at 22, being freely rotatably mounted at one end of a frame 23 to the opposite side of which an operation stand 24 is attached. The frame 23 is attached to the lower end of a vertical suspension element 25 which is telescopically connected to an upper vertical suspension element 26. The element 26 is at its upper end rigidly connected to a horizontal arm 27 being at its free end rotatably mounted about a vertical axis in a bearing 28. The arm 27 can be locked in the position shown in FIG. 9 by means of a bolt 29. Within the hollow elements 25, 26 a lifting and lowering mechanism 30, 31, prefer-ably a hydraulic mechanism is provided, by means of which the frame 23 together with the tool 22 and operation stand 24 can be raised and lowered.

The numeral 32 designates a crane which can be moved on a rail 33 in parallel with the electrolytic cell or row of cells in which the crust is to be broken. The crane 32 has a horizontal beam 34 at the free end of which the bearing 28 is supported. The crane is at its upper end guided by a rail 35 and rollers 36.

The numeral 37 designates an electrolytic cell with a crust 38 which should be broken or pressed down by means of the crust breaking apparatus. It will be understood that a number of such cells are usually arranged in a row in parallel with the rail 33.

The crust breaking apparatus shown in FIG. 9 operates as follows:

When the apparatus is to be started, the crane 32 is moved to one end of the row of cells, or to some other place where it is desired to start the breaking of the crust. By means of the mechanism 30, 31 the frame 23 with operation stand 24 and tool 22 is lowered until the tool is forced partly through the crust, as shown in FIG. 9. During this movement, the tool will make a hole in the crust, or press the same down into the electrolytic bath. The movement of the crane is now started, while the tool is kept in constant height relatively to the surface of the crust. The tool itself operates as described in connection with FIGS. 1 and 2.

As a result of the resistance which the crust exerts against the movement of the tool, the frame 23 and its suspension means are submitted to a torque about the axis of the suspension means. In order to Withstand this torque and transfer it to the crane and its rails, the telescopic elements 25, 26 are made with sections of a shape differing from a circle, preferably with square sections as shown in FIG. 10. In this figure guiding elements 27a are shown between the elements 25 and 26. The torque caused by the movement of the tool on the crust will be transferred through the elements 25, 26 to the arm 27 and from this to the bearing 28, bolt 29, beam 34 and to the rails 33 and 35.

When the tool arrives at the end of the first cell, the frame 23 with operation stand 24 and tool 22 is raised so that the tool can be moved over the end wall of the cell and the adjacent end wall of the subsequent cell. Then the frame is anew lowered until the tool has reached its operation level, and the movement of the crane continues. When the apparatus has reached the last cell in a row, and the tool 22 has been passed along the crust in this cell, the frame 23 is raised, the bolt 29 is removed and the arm 27 rotated about the axis of the hearing 28. Then the bolt 29 is anew placed into locking position, the movement of the crane is reversed, the frame 23 is lowered, as described above, and the tool is brought into operation position on the opposite side of the said cell, that is the left side in FIG. 9. The breaking of the crust on the left side of the cells in the row can now take place in the same manner as already described.

FIGS. 11 and 12 show an embodiment of the apparatus according to the invention, suitable for breaking the crust between two parallel anodes in a cell of the type shown in FIG. 11. The cell 41 is here provided with two parallel anodes 42 and 43 with an intermediate passage 44. The electrolytic bath 45 is covered by a crust 46 to be broken by means of the apparatus shown.

47 is a crane which can be moved on a rail 48. The crane has a horizontal beam 49 at the end of which is attached the upper 50, of two vertical, telescopic suspension elements 50', 51 and the upper end of a cylinder 52 in a hydraulic mechanism 52, 53. The lower end of the element 51 and the lower end of a piston rod 53 in the hydraulic mechanism are rigidly connected to a fork-shaped element 54 in which a tool 55, of the same type as described in connection with FIGS. 1, 2 and 9, is rotatably mounted.

Suspension rods 56 are carried by the beam 49, and carry at their lower ends an operation stand 57.

The function of the apparatus according to FIGS. 11 and 12 is substantially the same as the function of the apparatus described in connection with FIGS. 9 and 10. As a result of the resistance which the crust exerts against the movement of the tool 55, a bending moment is transferred to the elements 50, 51. These elements should therefore be shaped and dimensioned so that they are able to withstand this moment and transfer the same as a torque to the beam 49.

We claim:

1. Apparatus for breaking the crust in a metal-producing electrolytic cell containing a suspended electrode, comprising a support movable along the cell, a crustbreaking tool carried by said support, means for pressing the tool down against the crust to a position in which the lowermost point of the tool is situated a distance below a plane generally flush with the upper surface of the crust, means for moving said support along the cell, means for maintaining the tool in its lowered position during the movement of the support and the tool, said tool comprising a hub having a plurality of radially eX- tending elements, a substantially horizontal axis on said support substantially perpendicular to the direction of movement of said support on which said hub is rotatably mounted, whereby said hub and radially extending elements may roll on the surface of said crust and said elements are forced down through said crust.

2. Apparatus as claimed in claim 1 in which two sets of radially extending elements are provided on said hub, the elements in said two sets extending in parallel planes and being angularly displaced relatively to each other.

3. Apparatus for breaking the crust in a metal-producing electrolytic cell containing a suspended electrode, comprising a crane movable along the cell, a crustbreaking tool carried by said crane, means for pressing said tool down against the crust to a position in which the lowermost point of the tool is situated a distance below a plane generally flush with the upper surface of the crust, means for moving said crane along the cell, said tool comprising a hub having a plurality of radially extending elements, a substantially horizontal axis on said crane substantially perpendicular to the direction of movement of said crane on which said hub is rotatably mounted, whereby said hub and radially extending elements may roll on the surface of said crust and said elements are forced down through said crust, and means for maintaining said tool in its lowered position during the movement of said crane and tool.

4. Apparatus as claimed in claim 3 comprising sus pension means carried by said crane, a frame attached to the lower end of said suspension means carrying said tool and an operation stand carried 'by said frame.

5. Apparatus for breaking the crust in a metal-producing electrolytic cell containing a suspended electrode, comprising a crane movable along the cell, a telescopic suspension means carried by said crane, a frame attached to the lower end of said suspension means, a crustbreaking tool carried by said frame, said tool compris'ng a hub having a plurality of radially extending elements, a substantially horizontal axis on said frame, substantially perpendicular to the direction of movement of said frame on which said hub is rotatably mounted whereby said hub and radially extending elements may roll on the surface of said crust and said elements are forced down through said crust, an operation stand carried by said frame, means for lifting and lowering said frame, means for moving said crane along the cell and means for maintaining the tool in a lowered position in which the lowermost point of the tool is situated a distance below a plane generally flush with the upper surface of the crust during the movement of the crane.

6. Apparatus as claimed in claim 5 in which said suspension means is adapted to transfer the torque, caused by the resistance met 'by said tool when moving along the crust, from the frame to the crane.

References Cited by the Examiner UNITED STATES PATENTS 990,846 5/1911 Crandall 299-40 2,423,787 7/1947 Mosena et al. 299-37 X 2,890,872 6/1959 Hall 29940 2,964,305 12/1960 Samhammer et al. 29937 X ERNEST R. PURSER, Primary Examiner. 

1. APPARATUS FOR BREAKING THE CRUST IN A METAL-PRODUCING ELECTROLYTIC CELL CONTAINING A SUSPENDED ELECTRODE, COMPRISING A SUPPORT MOVABLE ALONG THE CELL, A CRUSTBREAKING TOOL CARRIED BY SAID SUPPORT, MEANS FOR PRESSING THE TOOL DOWN AGAINST THE CRUST TO A POSITION IN WHICH THE LOWERMOST POINT OF THE TOOL IS SITUATED A DISTANCE BELOW A PLANE GENERALLY FLUSH WITH THE UPPER SURFACE OF THE CRUST, MEANS FOR MOVING SAID SUPPORT ALONG THE CELL, MEANS FOR MAINTAINING THE TOOL IN ITS LOWERED POSITION DURING THE MOVEMENT OF THE SUPPORT AND THE TOOL, SAID TOOL COMPRISING A HUB HAVING A PLURALITY OF RADIALLY EXTENDING ELEMENTS, A SUBSTANTIALLY HORIZONTAL AXIS ON SAID SUPPORT SUBSTANTIALLY PERPENDICULAR TO THE DIRECTION OF MOVEMENT OF SAID SUPPORT ON WHICH SAID HUB IS ROTATABLY MOUNTED, WHEREBY SAID HUB AND RADIALLY EXTENDING ELEMENTS MAY ROLL ON THE SURFACE OF SAID CRUST AND SAID ELEMENTS ARE FORCED DOWN THROUGH SAID CRUST. 